a. Field of the invention
The present invention relates to automatic flash-photography and, more particularly, to an automatic flash-photographing arrangement in which the exposure time is automatically decided by an exposure-time control circuit when brightness of the object is high, the flash-photography being automatically carried out at a pre-determined shutter speed when brightness of the object is low.
B. Description of the prior art
When brightness of an object is high and it is possible to photograph it at a shutter speed higher than, for example, 1/30 sec., technical problems in photographing usually do not occur. When, however, brightness of the object is low and a favourable photograph cannot be obtained unless the shutter speed is lower than 1/30 sec., a problem of camera-shake is liable to exist. To solve this problem, the object is generally photographed a using flash-photography.
Using a modern camera of such type that the exposure time is automatically decided by an electronic control means, the necessity of flash-photography is either indicated by an warning lamp at the final stage of the shutter releasing operation or has to be judged based on the experience of the photographer. Shutter mechanisms are usually changed over from the state for photographing by natural light to the state in which flash-photography is possible by operating a lever, ring, etc. or by mounting a flash bulb to the camera body. Because of the above, known flash-photographing arrangement have disadvantages in that the release operating mechanism of the shutter becomes complicated and it is possible to miss the important shutter change while photographing. Additionally, in certain types of flash-photographing arrangements wherein the flash bulb is mounted to the camera body, the shutter speed is kept fixed at a particular value, for example at 1/30 sec., when said bulb is left mounted to the camera body after use and, consequently, photographing by natural light cannot be carried out.